Filter unique method references

Previously List was used to store found method references. This caused
the algorithm to perform reduntant search. Changing List to HashSet can
improve performance significantly on a larger project.

Author: Pawel Badenski

src/main/java/org/axonframework/intellij/ide/plugin/publisher/DefaultEventPublisherProvider.java

@@ -1,5 +1,6 @@
 package org.axonframework.intellij.ide.plugin.publisher;
 
+import com.intellij.openapi.fileTypes.StdFileTypes;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Condition;
 import com.intellij.psi.JavaPsiFacade;
@@ -18,29 +19,35 @@
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.Processor;
 import com.intellij.util.Query;
-import com.intellij.util.containers.ConcurrentMultiMap;
-import com.intellij.util.containers.MultiMap;
 
 import java.util.Collections;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import static java.util.Arrays.asList;
 
 class DefaultEventPublisherProvider implements EventPublisherProvider {
 
-    private final MultiMap<Project, PsiMethod> publisherMethodsPerProject = new ConcurrentMultiMap<Project, PsiMethod>();
+    private final Map<Project, Set<PsiMethod>> publisherMethodsPerProject = new ConcurrentHashMap<Project, Set<PsiMethod>>();
 
     @Override
     public void scanPublishers(final Project project, GlobalSearchScope scope, final Registrar registrar) {
         cleanClosedProjects();
-        publisherMethodsPerProject.putValues(project, findMethods(project, GlobalSearchScope.allScope(project),
+        Set<PsiMethod> psiMethods = publisherMethodsPerProject.get(project);
+        if (psiMethods == null) {
+            psiMethods = new HashSet<PsiMethod>();
+            publisherMethodsPerProject.put(project, psiMethods);
+        }
+        psiMethods.addAll(findMethods(project, GlobalSearchScope.allScope(project),
                 "org.axonframework.eventsourcing.AbstractEventSourcedAggregateRoot", "apply"));
-        publisherMethodsPerProject.putValues(project, findMethods(project, GlobalSearchScope.allScope(project),
+        psiMethods.addAll(findMethods(project, GlobalSearchScope.allScope(project),
                 "org.axonframework.domain.AbstractAggregateRoot", "registerEvent"));
-        publisherMethodsPerProject.putValues(project, findMethods(project, GlobalSearchScope.allScope(project),
+        psiMethods.addAll(findMethods(project, GlobalSearchScope.allScope(project),
                 "org.axonframework.eventsourcing.AbstractEventSourcedEntity", "apply"));
 
-        scanEventPublishers(scope, registrar);
+        scanEventPublishers(project, scope, registrar);
         scanCommandPublishers(project, scope, registrar);
     }
 
@@ -116,8 +123,8 @@ private PsiClass findCommandHandlersAnnotation(Project project) {
                         GlobalSearchScope.allScope(project));
     }
 
-    private void scanEventPublishers(GlobalSearchScope scope, final Registrar registrar) {
-        for (PsiMethod method : publisherMethodsPerProject.values()) {
+    private void scanEventPublishers(Project project, GlobalSearchScope scope, final Registrar registrar) {
+        for (final PsiMethod method : publisherMethodsPerProject.get(project)) {
             Query<PsiReference> invocations = ReferencesSearch.search(method, scope);
             invocations.forEachAsync(new Processor<PsiReference>() {
                 @Override
@@ -155,13 +162,13 @@ private void cleanClosedProjects() {
         }
     }
 
-    private List<PsiMethod> findMethods(Project project, GlobalSearchScope allScope, String className,
-                                        String methodName) {
+    private Set<PsiMethod> findMethods(Project project, GlobalSearchScope allScope, String className,
+                                       String methodName) {
         PsiClass aggregateClass = JavaPsiFacade.getInstance(project).findClass(className, allScope);
         if (aggregateClass != null) {
-            return asList(aggregateClass.findMethodsByName(methodName, true));
+            return new HashSet<PsiMethod>(asList(aggregateClass.findMethodsByName(methodName, true)));
         }
-        return Collections.emptyList();
+        return Collections.emptySet();
     }
 
     @Override